Margarita Armstrong-Jones is Queen Elizabeth's grandniece--the granddaughter of her only sister, Margaret (who, sadly, died just three months before Margarita was born). That makes her Prince William's second cousin.
Margarita must have been thrilled to ride in the same carriage as Pippa Middleton, Kate's glamorous sister and maid of honor. The 8-year-old had her own touch of glamour, too--and waved to the crowd along the route with the smile of a royal pro. Now she's 13, and studying in school.